Shouldn't people be screened for complement system deficiencies and/or dysfunction before being vaccinated? aren't vaccines harmful to these people?

No screening: If someone has symptoms of immune dysfunction, they should be tested for it. Screening a bunch of people for a relatively uncommon condition for which early intervention does not change the course of the disease does not make sense. Also, people with certain immune dysfunctions should be vaccinated. Depends on the vaccine and the dysfunction.

No: We recommend full vaccination for patients with complement deficiency. In fact, particularly with Neisseria and pneumococcus, these vaccines provide more benefit to complement-deficient individuals compared with the normal population.